This invention relates to the protection of buried optical fiber cables and more particularly to method and apparatus of making an earth working equipment or other operator aware of the fact that his equipment may be operated in the area of a buried optical fiber cable (OFC).
The use of buried OFC is becoming common place in the communication industry in both local and trunk applications. In the past it was not necessary to provide rodent protection of buried copper telephone cables that were used for trunk applications since the diameters of such cables were so large that rodents could not gnaw on them. Buried OFC is sufficiently small, however, (typically in the 3/4 to 11/2 inch outer diameter range) that it is susceptible to being gnawed on by rodents. It was therefore recommended at a recent Society of Photographic Instrumentation Engineers meeting that all buried OFC contain a metallic rodent shield, whether the cable is buried directly in the ground or pulled into ducting in the ground. A rodent shield is typically an electrically conductive corrugated bellows type sleeve made of aluminum, copper, or stainless steel that extends over the full length of the OFC so that the cable can be readily rolled up onto a spool. Alternatively, the rodent shield may be an electrically conductive wire mesh or braided sleeve. Additionally, the OFC may be formed with more than one rodent shield. And since buried OFC is underground and hidden from view it is continuously subject to damage by earth working equipment that may be carelessly or inadvertently operated in the area of such a cable.
An object of this invention is the provision of method and apparatus for protecting buried OFC.